The present invention relates to a developing treatment apparatus used in the process for manufacturing a semiconductor device, and a method for the developing treatment, in particular to an apparatus and a method applied to treatment for developing a photoresist which is formed on a semiconductor wafer and has a circuit pattern exposed to light, in a photolithography process.
As is well known, for the process for manufacturing a semiconductor device, a photolithography process is one important technique for forming various circuit patterns in a semiconductor wafer. The photolithography process is in general carried out in the following manner. Namely, a photoresist is coated onto a semiconductor wafer, and then this photoresist is exposed to light by the use of a lithographic apparatus which is referred to as a stepper to transcribe a circuit pattern. Subsequently, the photoresist is developed by an alkaline aqueous solution to obtain a resist pattern corresponding to the transcribed circuit pattern.
The above-mentioned the developing treatment apparatus and the process for the developing treatment, at first a semiconductor wafer to be treated is supported onto a spin chuck by vacuum suction. A photoresist is coated onto the main surface of this wafer and exposed to light by a stepper so that a circuit pattern is transcribed. An alkaline aqueous solution is then supplied from a developer supplying nozzle to the upper surface of the wafer and under the condition that the alkaline aqueous solution is strained and stretched on the surface by surface tension, development is carried out with this wafer being stopped or rotated at a low speed. After that, pure water is supplied from a washing liquid supplying nozzle onto the surface of the wafer to wash it. At the last step, the pure water is scattered off by rotating the wafer at a high speed to dry the surface of the wafer. Thus, a series of the development treatment is finished.
In the prior developing treatment apparatus and the process for the developing treatment as described above, however, the alkaline aqueous solution is jetted out from the developer supplying nozzle disposed to oppose the upper portion of the semiconductor wafer so as to supply the developer to the upper surface of the wafer. Therefore, when much difference in time when the developer starts to be supplied is caused depending on the position at which the pattern is disposed on the surface of the wafer or when scattering of the flowing speed of the developer jetted out from the nozzle occurs, uniform developing treatment cannot be carried out so that a measurement error is liable to be caused in the resist pattern.
Because the surface of the photoresist formed on the semiconductor wafer is highly hydrophobic, the surface is liable to repel the developer at the initial stage of jetting out the developer from the developer supplying nozzle so that turbulent flow of the developer is generated on the surface of the resist and bubbles are produced. The bubbles produced at the interface between the photoresist and the developer are a main cause of bad development and consequently the yield rate of the resist pattern is lowered.
As described above, in the prior developing treatment apparatus and the method for the developing treatment, there remains a problem that it is difficult to supply the developer uniformly on the surface of the photoresist and a measurement error easily occurs in the formed resist pattern. There also remains a problem that bubbles are produced on the surface of the photoresist and consequently the yield rate of the resist pattern is decreased.